Back-pressure valve



(No Model.)

0. P. COPELAND.

BACK PRESSURE VALVE.

Patented Jan. 23, 1883. F1 1.

UNITED STATES PATENT O FICE.

"CHARLES F. COPELAND, OF BOSTON, MASSACHUSETTS.

BACK-PRESSURE VALVE.

SPECIFICATION forming part of Letters Patent No. 270,890, dated January 23, 1883.

' Application filed May 27, 1882. (No model.)

To all whom it may concern.-

Be itknown that 1, CHARLES F. COPELAND a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvementsin Back-Pressure Valves for Gas, Air, or Steam; and I do hereby declare that the same are fully described in thefollowing specification, and illustrated in the accompanying drawings.

This invention relates to improvements in automatic back-pressure valves for gas, air, or steam, and it is carried out as follows, reference being had to the accompanying drawings, in which- Figure 1 represents a central longitudinal section; and Fig. 2 represents a. cross-section on the line A B shown in Fig. 1.

Similar letters refer to similar parts wherever they occur on the different parts of the drawings.

a represents the body or shell of the improved valve, having an exterior screw-th read inits lower end for connecting it with the reduce-coupling b and pipe 0, as usual. The up per end, a, of the shell a is also provided with an exterior screw-thread for connecting it to the reduce-coupling d and pipe 6, as shown. The shell a, at its junction with the upper screw-threaded portion a, has an annular offset, a, and farther on an annular chamber or recess, a, adapted to contain mercury f, to form aliquid seal for the inverted-cup valve 9, as shown in the drawings. The central portion of the inverted-cup valveg is secured to the vertical valve or guide rod h, which is screw-threaded in its upper end, and provided with regulating-nuts h and h, one below and one above the valve 9, as shown in'Flg. 1, by means of which the lift of the valve 9 out of the mercury f may be regulated and adjusted. The valve, or guide rod h passes through a central perforation in the upper cross-piece, a and also through a central perforation in the lower cross-piece, a which cross-pieces a and a are cast in one piece with the shell a, as shown, without obstructing the passage of the air'on gas throughsaid shell.

h isa head in the lower end of the valve or guide rod h, which acts as a stop against the under side of the lower cross-bar, a to prevent the inverted-cup valve from rising too far above its liquid seal when the pressure from below exceeds that from above. The full lines in Fig. 1 represent the inverted-cup valve'as in a closed position, with its annular rim sealed in the liquid mercury f, and the dotted lines in said Fig. 1 show the position of the valve when raised out of the liquid sealf. The annular offset a permits of a free and unobstructed passage of the gas, air, or steam when the valve 9 is raised out of its liquid seal.

This automatic back-pressure valve is "cry well adapted for the purpose of preventing the backward flow of gas to the blower of a carbureting-machine when such blower is at rest, and it may also to equal advantage be used for automatically preventing the backward flow of gas, steam, or air when the pressure above the valve exceeds the one from below.

What I wish to secure by Letters Patent and claim is The herein-described automatic back-pressure valve for gas, air, or steam, consisting of the body or shell a, with its guide-pieces a a and having annular offset a", and annular chamber a in its upper end, the liquid sealf, combined with the inverted-cup valve 9, and central guide-rod, it, having regulating-nuts h h in its upper end, and stop h in its lower end, as herein shown and described.

In testimony whereof I have affixed my signature in presence of two witnesses.

CHARLES F. COPELAND.

Witnesses ALBAN ANDRE'N, HENRY OHADBoURN. 

